题目

Some plays are so successful that they run for years on end. In many ways, this is 36 for the poor actors who are required to go on repeating the sane 37 night after night. One would  38 them to know their parts by heart and 39 have cause to falter（结巴）.Yet 40 is not always the case.A famous actor in a 41 successful play was once cast in the role of an aristocrat 42 had been imprisoned in Bastille for twenty years. In the last act，a gaoler（监狱长，看守）would always come on to the stage with a letter which he would hand to the prisoner. 43 the noble was expecte用含有少量镁的铝片制取纯净的Al（OH）3，可能有的步骤为：①加盐酸溶解；②加苛性钠溶液；③过滤；④通入过量CO2；⑤加过量纯碱溶液，实验操作最合理的组合及顺序是（ ）A．①⑤④③B．②③④③C．②③⑤③D．①⑤③